Humberto Moreira, who seems to have again been shamed into a lower profile following the Coahuila debt scandal --I say again because something similar happened in January after he talked and talked and talked and then the PRI was defeated in Guerrero and Baja California Sur-- says that AMLO is the PRI's principal adversary in 2012, not the PAN candidate nor Ebrard.
It seems untrue on the merits: AMLO has the highest negatives of any candidate, indeed of any major politician in Mexico. There's no way he could best Peña's vote total unless the former Edomex governor is caught with a dead body in his trunk, and even then it's not a guarantee. He also would seem to be boosting AMLO's profile with the comment, which probably dampens enthusiasm from Ebrard around the margins, which is likely the intended effect. Whatever the case, Chucho Ortega says it's not true, and accused the PRI of trying to impose a candidate on the PRD. Also, Ebrard, noting Moreira's unusual interest in the PRD's determination of a candidate, invited the PRI president to vote in the coming referendum which will (in theory anyway) determine the winner.